/* ============================================================
   base.css — shared design system for the 公考学习系统
   Load order: base.css → page css → account.css
   Tokens + primitives only; page layout lives in page css.
   ============================================================ */

:root {
  color-scheme: light;

  /* ---- Neutral palette ---- */
  --bg: #f5f7fa;
  --surface: #ffffff;
  --surface-alt: #f8fafc;
  --text: #1d2839;
  --text-muted: #5a6b84;
  --text-faint: #7c8aa0;      /* ≥15px or decorative text only */
  --line: #e2e8f0;
  --line-strong: #cbd5e3;

  /* ---- Dark chrome (top bars) ---- */
  --ink: #101828;
  --ink-hover: #1c2940;
  --on-ink: #ffffff;
  --on-ink-muted: #c6d0e0;
  --on-ink-line: rgba(255, 255, 255, 0.22);

  /* ---- Brand ---- */
  --primary: #2454d6;
  --primary-hover: #1e46b4;
  --primary-active: #193ca0;
  --primary-soft: #edf3ff;
  --primary-border: #c7d7fe;
  --on-primary-soft: #1a3fa8;
  --primary-ring: rgba(36, 84, 214, 0.22);

  /* ---- Semantic feedback ---- */
  --good: #067647;
  --good-soft: #ecfdf3;
  --good-border: #abefc6;
  --bad: #b42318;
  --bad-hover: #912018;
  --bad-soft: #fef3f2;
  --bad-border: #fecdca;
  --warn: #9a5b00;
  --warn-soft: #fff7ed;
  --warn-border: #fed7aa;

  /* ---- Typography ---- */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --text-xs: 12px;
  --text-sm: 13px;
  --text-md: 14px;
  --text-base: 15px;
  --text-lg: 17px;
  --text-xl: 20px;
  --text-2xl: 24px;
  --lh-tight: 1.35;
  --lh-body: 1.65;
  --lh-loose: 1.85;

  /* ---- Shape ---- */
  --radius-xs: 6px;
  --radius-sm: 8px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --radius-xl: 18px;
  --radius-full: 999px;

  /* ---- Elevation (used sparingly) ---- */
  --shadow-xs: 0 1px 2px rgba(16, 24, 40, 0.06);
  --shadow-sm: 0 1px 3px rgba(16, 24, 40, 0.09), 0 1px 2px rgba(16, 24, 40, 0.05);
  --shadow-md: 0 6px 18px rgba(16, 24, 40, 0.08);
  --shadow-lg: 0 16px 44px rgba(16, 24, 40, 0.18);

  /* ---- Motion ---- */
  --ease: cubic-bezier(0.2, 0.7, 0.3, 1);
  --dur-fast: 120ms;
  --dur-med: 180ms;

  /* ---- Spacing ---- */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 24px;
  --space-7: 32px;
  --space-8: 40px;

  /* Back-compat aliases (older page css referenced these names) */
  --panel: var(--surface);
  --muted: var(--text-muted);
  --primary-dark: var(--primary-active);
  --soft: var(--primary-soft);
  --ink-legacy: var(--text);
}

/* ============ Reset / base ============ */

* {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
}

body {
  min-height: 100vh;
  min-height: 100dvh;
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: var(--lh-body);
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, p {
  margin: 0;
}

img {
  max-width: 100%;
}

/* ============ Accessibility ============ */

.skip-link {
  position: absolute;
  top: -48px;
  left: 12px;
  z-index: 2000;
  padding: 10px 16px;
  border-radius: var(--radius-md);
  background: var(--ink);
  color: var(--on-ink);
  text-decoration: none;
  transition: top var(--dur-fast) var(--ease);
}

.skip-link:focus-visible {
  top: 12px;
}

:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ============ Utility ============ */

.hidden {
  display: none !important;
}

/* ============ Forms ============ */

label {
  color: var(--text-muted);
  font-size: var(--text-md);
}

input,
select,
textarea {
  width: 100%;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-md);
  padding: 10px 12px;
  background: var(--surface);
  color: var(--text);
  font: inherit;
  transition: border-color var(--dur-fast) var(--ease), box-shadow var(--dur-fast) var(--ease);
}

input:focus-visible,
select:focus-visible,
textarea:focus-visible {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-ring);
}

input::placeholder,
textarea::placeholder {
  color: var(--text-faint);
}

/* ============ Buttons ============ */

button {
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-md);
  padding: 9px 14px;
  background: var(--surface);
  color: var(--text);
  font: inherit;
  cursor: pointer;
  transition: background var(--dur-fast) var(--ease), border-color var(--dur-fast) var(--ease),
    color var(--dur-fast) var(--ease), box-shadow var(--dur-fast) var(--ease);
}

button:not(:disabled):hover {
  border-color: var(--text-faint);
  background: var(--surface-alt);
}

button:not(:disabled):active {
  background: var(--line);
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.45;
}

button.primary {
  border-color: var(--primary);
  background: var(--primary);
  color: #fff;
}

button.primary:not(:disabled):hover {
  border-color: var(--primary-hover);
  background: var(--primary-hover);
}

button.primary:not(:disabled):active {
  background: var(--primary-active);
}

button.secondary {
  color: var(--text-muted);
}

button.secondary:not(:disabled):hover {
  color: var(--text);
}

button.danger {
  border-color: var(--bad);
  background: var(--bad);
  color: #fff;
}

button.danger:not(:disabled):hover {
  border-color: var(--bad-hover);
  background: var(--bad-hover);
}

button.ghost {
  border-color: transparent;
  background: transparent;
  color: var(--text-muted);
}

button.ghost:not(:disabled):hover {
  border-color: transparent;
  background: var(--surface-alt);
  color: var(--text);
}

/* ============ Shared chrome: dark topbar + nav pills ============ */

.app-topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-6);
  padding: 18px 28px;
  background: var(--ink);
  color: var(--on-ink);
}

.app-topbar h1 {
  font-size: 21px;
  font-weight: 700;
  letter-spacing: 0.01em;
}

.app-topbar p {
  margin-top: 4px;
  color: var(--on-ink-muted);
  font-size: var(--text-sm);
}

.app-nav {
  display: flex;
  align-items: center;
  gap: 6px;
  min-width: 0;
  max-width: 100%;
}

.app-nav a {
  padding: 8px 14px;
  border: 1px solid transparent;
  border-radius: var(--radius-full);
  color: var(--on-ink-muted);
  font-size: var(--text-md);
  text-decoration: none;
  white-space: nowrap;
  transition: background var(--dur-fast) var(--ease), color var(--dur-fast) var(--ease);
}

.app-nav a:hover {
  background: rgba(255, 255, 255, 0.1);
  color: var(--on-ink);
}

.app-nav a.active {
  border-color: var(--on-ink-line);
  background: rgba(255, 255, 255, 0.14);
  color: var(--on-ink);
  font-weight: 600;
}

.app-nav a:focus-visible {
  outline-color: var(--on-ink);
}

@media (max-width: 900px) {
  .app-topbar {
    flex-wrap: wrap;
  }

  .app-topbar > * {
    min-width: 0;
  }

  .app-nav {
    overflow-x: auto;
    overscroll-behavior-x: contain;
    scrollbar-width: thin;
  }
}

/* Section labels shared across pages */
.eyebrow,
.section-kicker,
.exam-eyebrow {
  color: var(--text-muted);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.12em;
}

.app-topbar .eyebrow,
.app-topbar .exam-eyebrow {
  color: #93b1ed;
}

/* Cross-page components and states live in shared/components.css and
   shared/states.css. Keep this file limited to tokens, reset and primitives. */